1. Field of the Invention
The present invention relates to a dye-containing curable composition suitable for producing a color filter used in a liquid crystal display device and a solid state image sensing device, a color filter for electroluminescence, an ink for printing, an ink for ink-jet printing, and a paint, and also relates to a color filter using the dye-containing curable composition and a process for producing the same.
2. Description of the Related Art
As a process for producing a color filter used in a liquid crystal display device and a solid state image sensing device, a dyeing method, a printing method, an electrodepositing method and a pigment dispersing method have been known.
The dyeing method is such a method for producing a color filter in that a dyeing base material formed with a natural resin, such as gelatin, glue and casein, or a synthetic resin, such as an amine-modified polyvinyl alcohol, is dyed with a dye, such as an acidic dye. Since a dye is used as a coloring material in the dyeing method, there is a problem in light resistance, heat resistance and moisture resistance, and color unevenness is liable to occur in the case of a large size because dyeing and fixing characteristics are difficult to be uniformly controlled. Furthermore, a dyeing preventing layer is necessary upon dyeing, and thus such a problem arises in that the process becomes complicated.
The electrodepositing method is such a method for producing a color filter in that a transparent electrode is previously formed in a prescribed pattern, and a resin containing a pigment dissolved or dispersed in a solvent is ionized, to which a voltage is applied to form a colored image in the form of the pattern. In the electrodepositing method, a photolithographic process containing film formation and etching for the transparent electrode is necessary in addition to a transparent electrode for displaying. In the case where an electric short circuit is formed at this time, line defects are formed to cause reduction in yield. Furthermore, patterns other than stripe patterns, for example, mosaic patterns, are difficult to be applied in principle, and also, there is such a problem in that the transparent electrode is difficult to be handled.
The printing method is a simple method for producing a color filter by printing, such as offset printing, by using an ink formed by dispersing a pigment in a thermosetting resin or an ultraviolet ray curable resin. However, an ink that can be used has a high viscosity to make filtration difficult, whereby defects are liable to occur due to dusts, foreign matter and gelled matters of the ink binder, and there are problems in positional accuracy, line width accuracy and surface smoothness associated with printing accuracy.
The pigment dispersing method is a method for producing a color filter by a photolithographic process using a colored radiation sensitive composition containing a pigment dispersed in various kinds of photosensitive compositions. This method is stable to light and heat owing to the use of the pigment, and sufficient positional accuracy is ensured since patterning is carried out by a photolithographic process. Therefore, it is a method suitable for producing a color filter for a large size and high definition color display.
In order to produce a color filter by the pigment dispersing method, a radiation sensitive composition is coated on a substrate with a spin coater, a roll coater or the like and dried to form a coated film, and the coated film is exposed patternwise and then developed to obtain colored pixels. The operation is repeated for respective color hues to obtain a color filter.
As the pigment dispersing method, for example, JP-A No. 1-102469 and No. 4-76062 disclose negative photosensitive compositions using an alkali soluble resin with a photopolymerizable monomer and a photopolymerization initiator in combination. However, while higher definition is demanded for a color filter for a solid state image sensing device in recent years, the conventional pigment dispersing method inherently cannot improve resolution due to the pigment present in a particle state having a certain size, and there is a problem in formation of color unevenness due to coarse particles of the pigment. Therefore, it is not suitable for a purpose that requires a fine pattern, such as a solid state image sensing device.
In order to attain such a high resolution, techniques using a dye, which has been used as a coloring material, have been investigated, and two kinds of photosensitive colored compositions using a dye have been proposed, i.e., a positive photosensitive colored composition using a naphthoquinonediazide as a photosensitive material (as described, for example, in JP-A No. 2-127602), and a negative photosensitive colored composition using a photopolymerization initiator (using a crosslinking agent in combination) as a photosensitive material (as described, for example, in JP-A No. 6-75375). However, these photosensitive colored compositions have problems in solvent solubility, and also have such a problem in that the dye is poor in heat resistance and light resistance.
In view of the circumstances, a phthalocyanine compound can be considered as a dye excellent in heat resistance and light resistance. However, it is poor in solvent solubility, and in the case where the solvent solubility is intended to be improved, such a problem arises in that the heat resistance and the light resistance thereof are deteriorated. Therefore, it is the current situation that such a dye-containing curable composition and a color filter have not yet been provided that use a dye excellent in all solvent solubility, heat resistance and light resistance to provide excellent heat resistance and light resistance.
Under the circumstances, for example, a phthalocyanine dye with Cu, Co or Zn as a central metal having a bulky alkyl or alkoxy group introduced therein for improving the solubility thereof has been proposed in Canadian Journal of Chemistry, vol. 63, p. 623 to 631 (1985). However, the solubility in a halogenated hydrocarbon is improved, but the solubility to other solvents is still insufficient.
In view of improvement in solubility of a phthalocyanine dye, it has been investigated that a monosubstituent is introduced on the nitrogen atom of a metallic phthalocyaninesulfoneamide. For example, a compound having a primary alkoxyalkyl group bonded to the nitrogen atom is described in JP-A No. 3-195783. However, sufficient solubility has not yet been obtained thereby.